Vaccines containing antigens from more than one pathogenic organism within a single dose are known as “multivalent” or “combination” vaccines. Various combination vaccines have been approved for human use, including trivalent vaccines for protecting against diphtheria, tetanus and pertussis or against measles, mumps and rubella. These vaccines offer patients the advantage of receiving a reduced number of injections, which can lead to the clinical advantage of increased compliance (e.g. see chapter 29 of ref. 1), particularly in pediatric patients.
One difficulty when providing new combination vaccines is the potential for adverse vaccine-vaccine interactions between the mixed components, which may be due to physical or chemical factors. For instance, reference 2 discusses potential alterations in immunogenicity when antigens are combined, and reference 3 reports that the development of combination vaccines involves much more than the simple mixing of existing antigens. Similarly, reference 4 reviews a variety of clinically-relevant interactions (see also reference 5), and reference 6 reviews the technical challenges faced when making a combination vaccine.
It is an object of the invention to provide further and improved combination vaccines, and in particular those which can protect against serogroup B meningococcus and other pathogens.